Riderwood, MD Water Safety: 63/100 (2026)
1 ZIP code · 1 water system · Updated 2026-06-03
If you're checking Riderwood, MD tap water safety, the short answer is: average — violations are present in parts of the city and specifics depend on which water system serves your address.
How Riderwood Compares
Data: EPA SDWIS Last verified: 2026-06-03
What You Should Know About Riderwood Water
- Estimated remediation: $2,100 per household.
- CDC health risk index: 12.61 — above typical levels.
Who Supplies Your Water in Riderwood
Across most of Riderwood, MD, residential water comes from a single utility. That provider sets rates, manages infrastructure maintenance, and files compliance reports with the EPA on behalf of the households it serves. Federal tracking data shows 1 system on record, but one carries the bulk of the service load.
Overview
We track water quality and home safety data for 1 ZIP code in Riderwood, Maryland, covering 1 community water system serving approximately 1,600,000 people.
No EPA violations recorded across any ZIP codes in Riderwood — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for Riderwood: C (63/100)
The score combines three factors:
| Factor | What It Measures |
|---|---|
| Water Quality | EPA violations and compliance history |
| Lead Levels | 90th percentile lead concentration vs EPA action level |
| Radon Risk | EPA radon zone classification |
Water Sources
Riderwood water systems draw from: Surface water.
Lead & Copper
- Lead data: not yet available for Riderwood
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 2 (Moderate Risk)
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Areas with No Violations
| ZIP Code | Safety Score | System | Population |
|---|---|---|---|
| 21139 | C | CITY OF BALTIMORE | 1,600,000 |
All ZIP Codes in Riderwood
- 21139 [C]
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- Radon: EPA Map of Radon Zones
Updated daily.
Health Outcomes in Riderwood
Source: CDC PLACES (County-level estimates). Water contamination can correlate with respiratory and chronic health conditions.
Compared to National Average
Vertical line = national average. ■ Above national · ■ Below national
Flood & Climate Risk in Riderwood
Flood exposure in Riderwood is meaningful by NFIP measures — 2 claims on record and 100% of ZIP codes carrying FEMA flood zone designations. That level of activity makes flood history a relevant factor when evaluating local water quality over time.
Riderwood has a moderate flood history with 2 FEMA claims averaging $1,324 per payout. 100% of ZIP codes fall within FEMA flood zones. Flood events can contaminate drinking water and overwhelm treatment systems.
How flooding affects water quality: Flood events can introduce sewage, agricultural runoff, and industrial chemicals into water supplies. Even after floodwaters recede, contamination can persist in wells and aging infrastructure. Flood damage can add significantly to the estimated <strong>$2,100</strong> remediation cost per household.
Residents in flood-prone areas should consider flood insurance even outside FEMA zones — over 25% of flood claims come from low-to-moderate risk areas. After any flood event, test your water before drinking.
Source: FEMA National Flood Insurance Program (NFIP) claims data, FEMA flood zone designations.
What You Can Do in Riderwood
- Test your water at home. City-level data shows averages — your tap may differ. NSF-certified test kits cost $20-40 and give results in days.
- Install a certified water filter. An NSF-certified pitcher or under-sink filter removes most common contaminants.
- Check your home's plumbing. Homes built before 1986 may have lead solder in pipes. A licensed plumber can assess your risk.
Deep Dive Reports
Detailed analysis for Riderwood, MD